CVE-2026-120755
Description
A flaw was found in hdf5. An attacker could cause a Denial of Service (DoS) by convincing a user or application to process a specially crafted HDF5 file. When decoding szip-compressed data, the library does not verify that a data chunk is large enough before subtracting the header size, leading to an integer underflow and an out-of-bounds read that crashes the application.
Statement
An integer underflow and out-of-bounds read vulnerability exists in HDF5's H5Z__filter_szip() function within src/H5Zszip.c when decoding szip-compressed data. By convincing a user or application to read a dataset from a crafted HDF5 file containing a chunk smaller than the four-byte uncompressed-length header, an attacker triggers an integer wraparound during length calculation, leading to an out-of-bounds read and an application crash that results in a Denial of Service.
Mitigation
Disable szip filter support in HDF5 installations and builds where szip compression is not strictly required. Avoid opening or reading datasets from HDF5 files received from untrusted sources.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | 5.5 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | Required | Required | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
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